Shadow culling in shader for uv projected texture
I think what you are looking for is masking the actual texture out based on a camera direction.
I suggest you use the dot-product node in the shader graph.
The first input should be the mesh normals and the second input the projecting camera's direction. The result can be remapped using a color ramp node and then multiplied over the texture.
To get the camera's direction you could place an empty right down the z-axis of the camera and subtract the camera's position from the empty's position (maybe through a driver if necessary). If you have a lot of photos it could be a pain to manage the uvs and textures. Alternatively you could use a photogrammetry software like the opensource software MeshRoom to texture your mesh.